Bobbin-controlling mechanism for sewing-machines.



NOMODEL i APPLIOATION FILED ONT-2, 1899.

E [II g No. 723,330. PATENTED MAR. 24.1903. 1 j A. STEWART), DEGD.

A. J. STEWARD, ADMEINHTRATRIX.

BOBBIN CONTROLLING MECHANISM FOR SEWING MACHINES.

3 SHEETS-SHEET 1.

3 SHEETS-SHEET 3.

, H PATENTEDMAR. 24,1903. A. STBWARD, nncn. A. J. STBWAED, ADMINIS TRATRIX. 1301mm GONTROLLING MECHANISM FOR SEWING MACHINES.

APPLIOATION FILED OUT. 2, 1899.

umzmso. i

N0 MODEL UNITED STATES PAT NT FFICE.

AURELI US STEWARD, OF BRIDGEPORT, CONNECTICUT; ANNA J. STEWARD, ADMINISTRATRIX OF SAID AURELIUS STEWVARD, DECEASED, ASSIGNOR TO WHEELER & WILSON MANUFACTURING COMPANY, OF BRIDGEPORT, CONNECTICUT, A CORPORATION OF CONNECTICUT.

-BOBB IN CONTROLLING-MECHANISM FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent N 0. 723,330, dated March24, T903. Application filed (lGtObBI 2. 1899- sena No. 732,277. (No model.)

1'0 ail whom, it may concern: 7 Be it known that I, AURELIUS STEWARD, a 1 citizen of theUnited States, and a resident of Bridgeport, in the county of Fairfield and 5 State of Connecticut, have invented certain 7 new and useful Improvements in Sewing- Machines, of wh fication.

My invention'relates to sewing-machines IO of the so-called lock-stitch variety, in

which the interlocking of the threads is performed by a rotating or an oscillating hook,

. which seizes the loop of upper thread and passes it around a centrally-contained bobich the following is a speci- I5 bin carrying t-heunder thread, and has for its special object the drawing from the bobbin by cooperative, but independent, governable means and portioning ofi to the fabric whatever quantity of slackened under thread may be required for each successive stitch,

to the end that the lock may be readily and perfectly controlled and the stitching rendered more uniform and perfect, and other advantages, as will be hereinafter enumer- In machines of this class as at present constructed in drawing up the upper thread after its loop has passed around the bobbin -under favorable conditions the first resistance felt is that of the un relaxed u nder thread leading from the bobbin to the under side of the fabric, and the tension of'theupper thread must sufliciently predominate to first draw thread from the bobbin, a"fter which it must yield and supply thread for the completion of the stitch.

I am aware that by somekinds of interlocking mechanism a portion of the under thread required is drawn from the bobbin by theloop-taker or its propelling mechanism, 40 but such expedient affords but partial relief and, besides, promotes, difliculties scarcely less objectionable than those it seeks to obviate. Theamount to be drawn from the bobbin varies with different conditions. The

best seamsfor strength and for general purposes require that the point of interlocking, or the look, as properly termed, shall be intermediate with the'fabric, while if the uppersurface is the'exposed or right side of the garment the lock, especially on thin material, must be kept below, and if the under side is the right side the lock must be drawn above the center of the fabric, and the aptension, that of one and frequently of both threads being necessary to accomplish the desired result, and this means alone is incapable of controlling the location of the lock with accuracy for the following reasons: When the loop of upper thread has passed around the bobbin and meets the resistance of the under thread, before referred to, the tension of one thread is merely opposed to that of the other, both of which are caused to be more or less uncertain and variable by the unevenness of the'thread. When the strain of, say, the upper thread is increased by the passage of enlarged portionsthrough the tension-producing apparatus, the lock will be drawn up farther than when the opposite condition exists, and when one condition occurs with one thread simultaneous with the opposite condition with the other-the variation is doubly increased. So, also, a difference in the location of the lock will result as the bi'ght of the upper thread happens to clasp the under thread at varying distances from the previously-finished stitch. W'hen the threads are thus engaged near the preceding stitch, the under thread required must be drawn through the bight of the upper thread, and the upper tension will yield before drawing a sufficient quantity of lower thread from the bobbin, while if such engagement be nearer to the bobbin-case, the strain being more direct, the under, tension will sooner yield and give off more than the requisite amount of thread.

While it is evident that the advancement of the fabric by the feed-dog will draw from the bobbin a portion of the thread required for each successive stitch, the resulting strain of the thread upon fabrics of light texture is often greatly objectionable, and even at best this action can in no wise govern the varying quantity required for varying thicknesses or the placing of the lock above, below, or intermediate with the fabric, as occasion requires, all of which is attainable at the pleasure of the operator by the independently-controllable devices embodied in this invention.

In the accompanying drawings, which form a part of this specification, the bracket-arm of the sewing-machine which carries the needle-bar and presser bar as ordinarily used is entirely omitted, and only such portions of the frame or bed-plate, so called, are shown as are required to illustrate the construction and operation of the apparatus forming the subject of this application.

Figure 1 represents a bottom view ofa machine embodying my invention or a view of same when the bed-plate is inverted. Fig. 2 is a vertical section of the bed-plate on a line d d of Fig. 1. Fig. 3 is a vertical crosssection of the bed-plate exposing the operating-levers. Fig. 4 is a perspective view of my apparatus, together with the detachable bracket which carries theloop-taking apparatus or rotating hook, so called, of the sewing-machine. Fig. 5 is a plan view of the rotating hook, bobbin, and bobbin-case with thread being drawn from the latter; Fig. 6, the same parts with the under thread drawn from the bobbin and slackened preparatory to being drawn up into the fabric forthe completion of the stitch; and Figs. 7, 8, and 9, sections of sewed fabric with theinterlockings of the threads in different positions, as controllable by my devices without recourse to a change of tension upon either thread.

The general character of the sewing-machine in which my invention is in this case incorporated is that of the well-known Wheeler 85 Wilson vertical-hook variety, which is fully illustrated and described in United States Patent No. 578,136, issued March 2, 1897, and the entire apparatus above the bedplate, as also the feeding mechanism of whatever nature, whether an under feed carried in the bed-plate or an upper feed as carried in the bracket-arm of the sewing-machine, may all be of the usual construction, as they have no direct connection with this invention. The main propelling instrumentality in machines of this variety consists of two revolving shafts connected by quartering-cranks and connecting-rods, as illustrated in Patent No. 405,205, issued June 11, 1889, the lower shaft only of which is shown in these drawings, which I will term the frame-shaft A, which may be seen mounted in the bed-plate B in Figs. 1 and 2. In this the vertical-hook system before referred to the construction has been modified by adding an auxiliary shaft 0, hung in bearings beneath the shaft A and operatively connected therewith by means of gear-wheels D and D, all as more clearly shown in Fig. 2. The shaft 0 is in turn operatively connected with the lower end of the vertical shaft of the loop-taker or rotating hook E by means of the pair of beveled. gears F F, likewise more clearly shown in Fig. 2. The rotating hook E is carried in a detachable bracket G, depending from the bed-plate B for that purpose. The gears F F are uniform in size, while the gear-D is twice the size of the gear D in order that the rotating hook E may revolve twice to each revolution of the driving-shaft A for purposes hereinafter explained.

As far as described the mechanism is such as is in common use. To the bracket G, however, I attach by means of a pivot-screw H the thread-feeding lever K. (Best' seen in Figs. 3 and 4.) This lever, whose principal member is practically perpendicular, is provided with a horizontally-extended limb h for purposes hereinafter explained.

In this construction the bobbin, which is of the usual character, is contained within the bobbin-case L, which case is provided with the usual tension-spring, the stop Z, so called, and a flange H, which enters a groove provided therefor within the cavity of the rotating hook E; but as this style of loop-taker, bobbin, and bobbin-case has been fully described in United States Patent No. 480,181, issued August 2, 1892, a further description is not deemed necessary. It will be seen that by such construction the bobbin-case is circuniferentially journaled within the rotating hook, which imparts to the bobbin-casea tendency to revolve with the hook; but as the orifice from which the bobbin-thread leads must be practicallystationary it becomes necessary to restrain the bobbin-case L from revolving when in operation. This has heretofore been done by a notch in some immovable part, the notch being of such width as to embrace the stop Z with sufficient looseness to permit the free passage of the loop of the upper thread. (Not shown.) In this vertical-hook system it consisted of two adjacent projections depending from the throat-plate,so called, (shown at p in Fig. 3,) which projections embraced the stop Zfor the purpose stated. In my device, however, these projections are removed from the throat-plate, and the thread-feeding lever K is made to extend in close proximity to the under side of the throat-plate, and its horizontally-extended portion at its upper end is notched beneath to loosely embrace the stop and restrain the case from turning, except to the limited extent which it is caused to turn by the action of the thread-feeding lever K, as will be hereinafter more fully explained. v

Into the detachable bracket G, I also insert through a hole provided therefor the short horizontally-lying shaft N, whose outer end, as seen in Fig. 4, is provided with a securelyattached horizontally-lying lever O, which underlies the limb h of the thread-feeding lever K. To the farther end of the shaft N is fixedly attached a longer lever B. (Shown partially in dotted lines in Fig. 4.)

Upon the lowerend of the fulcrum-leverT is pivotally attached the sliding contact-piece U, whose cylindrical termination is turned at right angles and lies between the horizontal memberh of the thread-feeding lever K and the lever 0, carried upon the shaft N. The opposite end of the adjusting-rod S, which terminates near the base of the bracket-arm (not shown) of the sewing-machine, is supported bythe boss j, Fig. 1, which may be attached to or made integral with the bed-plate :B. At the extremityof the rod S is permanently attached the adjusting-lever V, which extends upward' through a hole provided therefor in the bed-plate B.

The detachable bracket G has heretofore been only of sufficient size to serve its original purpose of carrying the rotating hook E with its contained parts and its perpendicu lar shaft and attached beveled gear; but as the most available means for accomplishing my purpose I so enlarge thebracket G as to provide support for the shafts, &c., which have been applied thereto, as described.

Above the bed-plate B, in close proximity to the adjusting-lever V, is permanently at- 1 tached the index-plate K, through the areshaped slotof which is passed the adjusting thumb-screw Y, which enters a threaded hole therefor near the upper end of the lever V and which when tightened will retain the adjusting-lever in any desired position.

Upon the extreme end of the shaft A is secured the eccentric A, (best seen in Figs. 2 .,and3,) which by acting-upon the lever R,

through the medium of the shaft N, the lever i O, and the intermediate contact-piece U, im-

parts movement to thethread-feeding lever fK in one direction, while its attached coiled spring Y,1whose other end is affixed to a pin in bracket G, actuates it in the opposite direction, thereby imparting a vibratory m ovement to the thread-feeding lever K at each a revolution of the shaft A. The extent of the vibratory movement may be regulated through the instru mentality of the adjustinglever V, the rod S, the lever T, and the contact-piece U and theparts held in position 551 Y 14, the contact-piece U stands over the pivotal centerof the lever O, and hence receives no movement therefrom and imparts no action to the thread-feeding lever K. If, howas placed by tightening the thumb-screw Y. When the adj usting-lever is moved to the full extent in the direction shown in Figs. 3 and ever, the adjusting-lever V be so moved as to carry the contact-piece U away from the pivotal center of the lever 0, action will be imparted to the thread-feeding lever K, and the extent of such action is fully controllable bymeans of the adjusting-lever V, as vary- 1 ing conditions may require. a

As the action of the needle and the rotatto complete the operation in the formation of the lock-stitch are so well understood, it is not deemed necessary to encumber the drawings with illustrations of these operations. Suffice it to say that in the use of the vertical hook illustrated in the drawings the needle punctures the fabric at a point in relation to the hook shown by the circle of dotted; lines at 'i in Figs. 5 and 6. From that location the loop is delivered from the needle to .the rotating book, by the revolution of which it is enlarged, one portion of the loop passing beneath, while the other portion sweeps over the top of a bobbin-case L preparatory to being drawn up by the take up in the completion of the stitch. In this con struction the hook makes two revolutions to each one of the main shafts, as hereinbefore stated, and hence to each puncture of the needle and the formation of each stitch in order that the thread may be passed around the bobbin quickly to allow more time (during which the hook is making a non-efiective circuit) for the action of the feed-dog in advancing the fabric and the take-up in tightening of the stitch. In other constructions the rotating hook is propelledby mechanism which imparts to it a variable motion, which accelerates its movement during the passage of the loop around the bobbin and retards it during the succeeding operations. In still other constructions the loop-taker is propelled by some member other than an attached revolving shaft and passes through the loop,together with the bobbin,as in United States Patent No. 328,165, issued October 13, 1885, and others not necessary to enumerate; but whatever the character of such interlocking device the cooperation of my apparatus therewith is equally effective and advantageous.

By reference to Fig. 5 it will be seen that as oscillatory movement is imparted tothe bobbin-case L in the manner alreadydescribed as the bobbin-case is turned upon its pivotal center in one direction the orifice from which the under thread leads will recede from the needle-hole, and thereby draw thread from the bobbin, which thread by the movement of the bobbin-case in the opposite direction will be given up to the fabric for the formavtion of the succeeding stitch. The movement of the thread-drawing lever K, and hence the amount of under thread thereby supplied for each stitch, is perfectly controllable by the adjusting-lever V in the manner before described. By this process little care need be given to equalizing or balancing the tensions. When once set,with the under tension slightly predominating, the whole range of ordinary work may be accomplished without further regard to the tensions. When desirable to have the lock, say, intermediate with the fabri c, as shown in Fig. 7, such action is given to the thread-drawing lever K as will draw sufficient under thread to reach the desired position. When the varying conditions before cited require a change, the lock may be placed anywhere between the limits shown in Figs. 8 and 9 by a single movement of the adjusting-lever V. As the operative mechanism of the thread-drawing device is independent, its action is so timed in relation to other movements that it will draw thread from the bobbin only after one stitch is entirely finished and then relax the thread as demanded for the succeeding stitch. The stitch having been finished and advanced by the action of the feed-dog beyond the edge of the needle-hole in the throat-plate is in such position as to fully resist displacement of the lock by the action of the thread-feeding lever in drawing thread from the bobbin for the succeeding stitch. By feeding the under thread to the fabric in a perfectly slackened condition, as previously described, the upper thread is entirely relieved of the duty of drawing the thread from the bobbin against the resistance of the under tension, and hence is subjected to no strain, except in actually tightening the stitch, for which reason a greatly-diminished degree of tension only is required upon the upper thread, and hence the lowest grades of thread may be used with perfect success where strength of the seam is not a necessary requisite. By the operation of these devices the under thread is measured and portioned off with mechanical accuracy to the fabric as demanded, and the locks are not only readily controlled at the pleasure of the operator, but .are laid in the finished stitches with a degree of accuracy and certainty which has not to my knowledge been heretofore attained.

I do notwish to be limited to the exact construction herein shown and described, since it is obvious that the various elements may be greatly altered without departing from the spirit of my invention-as, for instance, the thread-drawing apparatus may be so constructed as to be operatively connected with any portion of the machine which will actuate it at the proper time instead of by a special eccentric, as herein shown and described, as the gist of my invention resides in the broad idea of equipping a sewing-machine with adjustable means whereby any desired and predetermined quantity or length of under thread may be supplied from the bobbin to the fabric at each stitch, the adjustment of said means being independent of the adj ustments of the remaining instrumentalities of the machine and the location of the threadlocks thereby controlled by the operator without recourse to the tension devices proper of the sewing-machine.

What I claim as my invention, and desire to secure by Letters Patent, is-

1. In a sewing-machine of the class described, having thread tension controlling mechanism, a feed mechanism, a bobbin, means to draw from said bobbin any predetermined length of under thread, and independent means to adjust the thread-drawing device, capable of manual control independently of the tension-controlling mechanism and the feed mechanism, whereby the operator may control the location of the threadlocks independently of the tension devices.

2. In a sewing-machine having stitch-forming and cloth-feeding mechanisms, a bobbin, a bobbin thread-puller and means to adjust said thread-puller manually at the will of the operator and independently of the stitchforming and cloth-feeding mechanisms, and means to actuate said thread-puller automatically and independently of the stitch-forming mechanism.

3. In a sewing-machine of the class described, a bobbin, avibratory lever engaging said bobbin, means to move said lever positively in one direction, a manually-controlled setting device for controlling the length of throw of said lever, and automatic means to move the lever in the opposite direction.

4. In a sewing-machine of the class described, a bobbin, a vibratory lever engaging such bobbin, a rock-shaft adjacent to said lever, and a shiftable contact-piece interposed between the lever and rock-shaft to vary the length of vibration of said lever.

5. In a sewing-machine of the class described, a bobbin, a vibratory lever engaging said bobbin, a rock-shaft and means to actuate it, a shiftable contact-piece interposed between the lever and shaft, and a contactpiece-adjusting device arranged within convenient reach and sight of an operator and controllable manually.

6.In a sewing-machine of the class described, a bobbin, a vibratory lever engaging said bobbin, a rock-shaft having a lever underlying the vibratory lever and a rockerlever, acam for engaging said rocker-lever,

a shiftable contact-piece interposed between the vibratory lever and the underlying lever of the rock-shaft, an adjusting-rod carrying said contact-piece, and means to set said rod to vary the throw of the vibratory lever and so control the location of the thread-locksindependently of the remainder of the machine.

Signed at Bridgeport, in the county of Fairfield and State of Connecticut, this 30th day of September, A. D. 1899.

AURELIUS STEWARD.

Witnesses:

J. S. FINOH, O. N. WORTHEN. 

